Increased risk of non-insulin dependent diabetes mellitus at low plasma vitamin E concentrations: a four year follow up study in men.

OBJECTIVE

To investigate whether low vitamin E status is a risk factor for incident non-insulin dependent diabetes mellitus.

DESIGN

Population based follow up study with diabetes assessed at baseline and at four years.

SETTING

Eastern Finland.

SUBJECTS

Random sample of 944 men aged 42-60 who had no diabetes at the baseline examination.

INTERVENTION

Oral glucose tolerance test at four year follow up.

MAIN OUTCOME MEASURES

A man was defined diabetic if he had either (a) a fasting blood glucose concentration > or = 6.7 mmol/l, or (b) a blood glucose concentration > or = 10.0 mmol/l two hours after a glucose load, or (c) a clinical diagnosis of diabetes with either dietary, oral, or insulin treatment.

RESULTS

45 men developed diabetes during the follow up period. In a multivariate logistic regression model including the strongest predictors of diabetes, a low lipid standardised plasma vitamin E (below median) concentration was associated with a 3.9-fold (95% confidence interval 1.8-fold to 8.6-fold) risk of incident diabetes. A decrement of 1 mumol/l of uncategorised unstandardised vitamin E concentration was associated with an increment of 22% in the risk of diabetes when allowing for the strongest other risk factors as well as serum low density lipoprotein cholesterol and triglyceride concentrations.

CONCLUSIONS

There was a strong independent association between low vitamin E status before follow up and an excess risk of diabetes at four years. This supports the theory that free radical stress has a role in the causation of non-insulin dependent diabetes mellitus.